Soda ash is primarily used in water treatment processes to achieve which of the following?

Soda ash, also known as sodium carbonate, is primarily used in water treatment processes to adjust pH. This compound helps to raise the pH of water, making it less acidic. Maintaining proper pH levels in water is crucial for various treatment processes, including coagulation, disinfection, and overall water quality management. By adjusting pH, soda ash can improve the efficiency of these processes and help to stabilize the water for distribution.

In contrast, while other options mention important aspects of water treatment, they do not accurately reflect the primary use of soda ash. Removing particulate matter typically involves filtration or coagulation with agents like aluminum sulfate or ferric chloride, which directly target debris rather than pH adjustment. Enhancing taste and odor often involves different chemicals and processes, focusing on organics or compounds that affect sensory perception rather than pH balance. Increasing water hardness is associated with adding minerals like calcium or magnesium, rather than altering pH with soda ash. Therefore, the primary function of soda ash in water treatment centers around pH adjustment.